With the advent of process-oriented research, the strategy studies have found their place in L2 composition pedagogy. One such issue is investigation into the impact of writing strategy use on increasing the quality of writing product. The present study investigates the potential relationship between writers’ proficiency level and strategy use, the nature of such strategies, if any, and whether any of them predicts good writing. The participants, 23 Iranian EFL graduates and undergraduates taking their essay writing course, were requested to write an essay of controlled length on a given topic. Based on their scores on a standardized test of language proficiency, the students were assigned to the elementary, intermediate, and advanced levels. Next, they attended an interview with the researcher, reading their essays and reporting what processes they underwent and what strategies they used as they produced the text. The students were provided with a strategies checklist to identify theirs, or to add new ones, if any. The think-aloud protocols were tape-recorded. Data analysis aimed to identify writing strategies as implemented by each student at the specified level. Surprisingly, lack of similarity in writing behavior among members of supposedly homogeneous and across different groups was observed. Moreover, increasing free voluntary reading and writing, decreasing writing apprehension, and of course practice were characterized as predictors of writing success.